Portable speaker



FIG. 1 is a front perspective view of a portable speaker showing our new design;

FIG. 2 is a top view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a rear view thereof;

FIG. 6 is a right side view thereof; and,

FIG. 7 is a left side view thereof.

The broken line showing of the various unshaded elements of the portable speaker illustrates environmental structure and forms no part of the claimed design. 

CLAIM The ornamental design for a portable speaker, as shown and described. 